1. He (has not answered) my letter yet.
2. Have you ever (eaten) caviar?
3. She has already (become) a student.
4. They (have travelled) all over the world.
5. How long have you (been) here?
6. I saw her in May but I (have not seen) her this month.
7. My friend (has bought) a new car.
8. I (have lost) my gloves.
9. I have never (riden) a camel.
10. They have never (behaved) like this before.